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THE  CHOW   IIT    ITS  HELATIOB   TO  AGRICULTURE 
Farmers  Bulletin  1102 


TJtam 


Farmers'  Bulletin  1102        United  States  Department  of  Agriculture, 


THE 

IN  ITS  RELATION  TO 

AGRICULTURE 


IsItaFarmflest? 


/~, 


THE  GROW  is  best  known  by   the   unfavorable 
reputation  it  has  acquired  in  the  cornfield.     No- 
torious also  are  its  raids  on  the  poultry  yard,  its 
depredations  on  wild  birds,  and  its  attacks  on  crops 
other  than  corn. 

Less  heralded,  however,  but  no  less  important  to 
the  farmer,  is  the  crow's  warfare  on  insect  pests. 
Insects  supply  about  one-fifth  of  its J"ood,  and  those 
preyed  upon  include  some  of  the  worst  pests  with 
which  the  farmer  has  to  contend  —  grasshoppers, 
caterpillars,  and  white  grubs  and  their  parents,  May 
beetles. 

From  the  evidence  at  hand  the  crow's  merits  and 
shortcomings  appear  about  equally  divided.  While 
it  would  be  unwise  to  give  it  absolute  protection,  and 
thus  afford  the  farmer  no  recourse  when  the  bird  is 
doing  damage,  it  would  be  equally  unwise  to  adopt 
the  policy  of  killing  every  crow  that  comes  within 
gunshot. 

Much  of  the  good  the  crow  does  can  ill  be  spared, 
and  the  damage  it  inflicts  may  be  materially  lessened 
by  proper  measures  against  such  birds  as  prove  to 
be  a  nuisance. 


Show  this  bulletin   to  a  neighbor.     Additional  copies  may  be  obtained  free 
from  the  Division  of  Publications,  United  States  Department  of  Agriculture. 


Contribution  frojn  Jije.Bji{ea&i  of  Biological  Survey 

'•'.':         J& A-:  1$£JJ5QF,  Chief 
Washington;  D;  G. •' ^  August,  1920 


THE  CROW  IN  ITS  RELATION  TO  AGRICULTURE. 


E.  R.  KALMBACH,  Assistant  Biologist. 


Distribution   and   abundance 

Life    history 

Economic    status 

Animal    food 

Insects  

Spiders,  fishes,  reptiles,  etc_ 
Wild  birds  and  their  eggs_ 

Poultry  and  their  eggs 

Mammals 

Carrion  and  the  distribu- 
tion of  live-stock  dis- 
eases   

Vegetable   food 

Corn 

Other    grains 


CONTENTS. 


Page. 

4 

5 

7 

7 

7 

10 

10 

10 

11 


Economic  status — Continued. 
Vegetable  food — Continued. 

Other   crops  

Wild   fruits 

Distribution  of  seeds 

Summary  of  food  habits 

Protection  of  crops  and  poultry. 

Frightening  devices 

Deterrents 

Scattering  grain 

Poisoning 

Trapping 

Shooting 

Destroying  nests 

Summary 


Page. 


12 
13 
13 
13 
15 
15 
16 
17 
17 
19 
19 
19 
19 


JT  IS  DOUBTFUL  whether  any  other  bird  is  of 
as  great  economic  importance  to  the  farmer  of  the 
eastern  United  States  as  the  crow.  In  food 
habits  it  is  practically  omnivorous ;  it  takes  any- 
thing from  the  choicest  poultry  and  the  tenderest 
shoots  of  sprouting  grain  to  carrion  and  weed 
seeds,  many  of  which  offer  at  best  but  a  morsel 
of  nourishment.  The  fact  that  no  less  than  656 
different  items  have  been  identified  in  its  food 
gives  some  idea  of  the  bird's  resourcefulness  and 
its  potentiality  for  good  or  harm.  Some  of  the 
complaints  against  the  crow  are  well-nigh  tradi- 
tional, while  a  few  of  its  beneficial  habits  have  long  been  matters 
of  common  knowledge.  Irreconcilable  differences  of  opinion  regard- 
ing the  crow's  worth  have  often  been  the  rule  among  residents  of  a 
community,  and  it  has  been  only  recently  that  sufficient  information 
has  been  assembled  from  most  parts  of  the  bird's  range  to  allow  a 
thorough  study  of  its  habits.1 

1  For  a  comprehensive  treatise  on  the  economic  status  of  the  crow  based  on  the  exami- 
nation of  the  food  contained  in  2,118  stomachs,  see  Bulletin  No.  621,  U.  S.  Dept.  Agr., 
"The  Crow  and  Its  Relation  to  Man,"  by  E.  R.  Kalmbach,  92  pp.,  2  pis.,  3  figs.,  Feb. 
16,1918.  ?Hkr  '•  •"*  .'/-UVS-." 

3 


434990 


Farmers'  Bulletin  1102. 


DISTRIBUTION   AND   ABUNDANCE. 

Although  the  crow  is  so  well  known  to  farmers  in  the  Eastern 
States  that  one  would  hardly  suppose  it  could  be  confused  with  other 
birds,  considerable  uncertainty  in  identification  exists  in  regions 
where  it  is  scarce  or  where  its  range  overlaps  that  of  closely  related 
species.  Ordinarily  little  distinction  is  made  by  the  residents  of  the 
South  Atlantic  coast  between  the  common  crow  and  the  fish  crow — 
a  bird  of  quite  different  habits ;  and  the  same  lack  of  distinction  is 
shown  by  the  average  individual  of  the  northwest  coast,  where  the 
northwestern  crow,  also  a  maritime  species,  mingles  with  the  com- 
mon form.  In  the  Southwest  the  small  white-necked  raven  is  fre- 
quently called  a  crow,  and  in  some  other  parts  of  the  West  even  the 
larger  ravens  have  been  similarly  misnamed. 

There  are  within  the  borders  of  the  United  States  three  species  of 
crows.  By  far  the  most  abundant  and  widely  distributed  form  is  the 
common  crow.1  This  bird,  with  its  three  closely  related  varieties,  the 
Florida  crow,2  the  southern  crow,3  and  the  western  crow,4  occupies  a 
range  comprising  practically  all  of  our  country  east  of  the  Rocky 
Mountains,  as  well  as  sections  in  the  Northwest  and  along  our  west- 
ern coast  as  far  as  southern  California.  It  also  is  found  locally  in 
parts  of  Arizona  and  New  Mexico.  The  other  two  species  are 
smaller  and  of  maritime  habits.  The  fish  crow,5  whose  notes  are  not 
greatly  different  from  those  of  the  young  of  the  common  crow, 
occupies  a  narrow  strip  along  the  Atlantic  and  Gulf  coasts  from 
Connecticut  to  Texas,  and  is  seldom  found  more  than  twenty  miles 
from  salt  water.  Its  counterpart,  the  northwestern  crow,6  which 
some  authorities  consider  simply  a  subspecific  form  of  the  common 
crow,  occupies  the  Pacific  coastal  region  from  Puget  Sound  to 
southern  Alaska. 

The  wrhite-necked  raven,7  inhabiting  the  arid  and  semiarid  sections 
of  Texas  and  southern  New  Mexico  and  Arizona,  is  the  raven  most 
frequently  confused  with  the  crow.  This  bird's  slightly  greater 
size,  the  white  bases  of  the  feathers  of  its  neck,  and  its  restricted 
range,  however,  serve  to  identify  it.  The  northern  raven,8  found 
along  our  northern  boundary  and  at  higher  altitudes  farther  south, 
and  the  common  raven,9  present  in  numbers  in  the  States  west  of 
the  Great  Plains,  may  be  distinguished  by  their  greater  size  and  by 
their  discordant  notes,  which  possess  none  of  the  lusty,  open-throated 
quality  of  those  of  the  crow. 

In  this  bulletin  the  name  "  crow  "  has  been  used  to  cover  the  four 
forms  of  the  common  crow,  including  the  close  relatives,  the  Florida, 
southern,  and  western  crows.10  The  food  habits  of  all  these  are  es- 

1  Corvus  brachyrhynchos   braohyrhynchos.  e  Corvus  caurinus. 

2  Cofvus  brachyrhynchos  pascuus.  7  Corvus  cryptoleucus. 

3  Corvus  brachyrhynchos  paulus.  s  Corvus  corax  principaUs. 
*  Corvus  brachyrhynchos  hesperis.  9  Corvus  corax  sinuatus. 

B  Corvus.  ossifragu*.  10  Corvus  brachyrhynchos,  four  subspecies. 


The  Crow  in  Its  Relation  to  Agriculture.  5 

sentially  the  same,  differing  only  to  an  extent  occasioned  by  the  vary- 
ing character  of  the  food  supply  in  the  different  parts  of  the  area 
covered  by  their  combined  ranges.  In  some  of  the  Western  States, 
where  the  crow  appears  only  as  an  occasional  breeder,  it  has  little 
economic  significance,  as  in  Nevada  and  the  greater  parts  of  Arizona, 
New  Mexico,  Colorado,  Wyoming,  Utah,  Idaho,  and  parts  of  Wash- 
ington and  Oregon.  It  can  be  considered  only  locally  abundant  in 
California.  The  western  parts  of  Texas,  Oklahoma,  Kansas,  and 


FIG.  1. — Young  .crows  nearly  ready  to  leave  the  nest. 

Nebraska  support  very  few  crows;  and  in  large  areas  of  Montana, 
North  Dakota,  and  South  Dakota,  and  in  the  Gulf  States  of  Florida, 
Alabama,  Mississippi,  and  Louisiana  crows  are  not  common.  Based 
on  the  average  yearly  abundance,  the  crow  exerts  its  greatest  eco- 
nomic influence  in  the  States  along  the  Atlantic  coast  north  of  North 
Carolina  and  in  the  central  and  upper  Mississippi  Valley. 

LIFE   HISTORY. 

The  nest  of  the  crow  is  built  at  heights  varying  from  20  to  60  feet, 
and  during  the  breeding  season  it  is  usually  well  concealed  from  be- 
low by  foliage.  Sometimes  it  is  placed  in  the  dense  top  of  a  pine,  but 
oaks  and  elms  of  the  river  bottoms,  and,  in  the  West,  cotton  woods  are 
equally  acceptable.  The  nests  are  rarely  found  in  deep  forests.  In 


6 


Farmers'  Bulletin  1102. 


the  East  the  hilly  and  partially  wooded  sections  of  New  Jersey,  New 
York,  and  Pennsylvania  seem  to  meet  nesting  requirements ;  in  Ohio, 
Indiana,  and  Illinois  the  low  fertile  river  bottoms  are  especially  at- 
tractive ;  and  farther  west  the  limited  tree  growth  confines  the  breed- 
ing activities  of  crows  to  the  neighborhood  of  streams. 

Crows  raise  one  brood  of  from  3  to  7  young  (see  fig.  1).  In  the 
Southern  States  the  young  may  be  found  in  the  nest  as  early  as  the 
middle  of  March  and  farther  north  correspondingly  later,  so  that 
along  our  northern  border  they  may  be  present  as  late  as  July.  The 
nestling  life  lasts  about  three  weeks.  For  some  time  after  the  brood 
of  the  year  has  left  the  nest,  in  July,  August,  and  September,  crows 
may  be  found  in  family  parties  or  in  small,  loose  flocks  of  10  or  a 


FIG.  2. — Location  of  crow  roosts  known  to  have  been  occupied  in  the  winter 

of  1911-12. 

dozen,  securing  much  of  their  food  from  grasshoppers  and  ripening 
corn. 

While  crows  are  more  or  less  clannish,  even  in  the  nesting  season, 
their  gregarious  habit  is  most  highly  developed  during  the  colder 
months,  when,  often  by  thousands,  they  resort  to  their  nightly  roosts. 
This  flocking  is  of  considerable  economic  significance  in  that  it  re- 
sults in  the  gathering  together  of  large  numbers  of  birds  possessing 
some  injurious  habits.  In  the  latitude  of  Washington,  D.  C.,  their 
roosts  are  well  established  by  the  end  of  September,  and  by  midwinter 
their  combined  southerly  migration  and  gregarious  habits  have 
brought  together  in  a  comparatively  small  area  the  bulk  of  the 
crow  population  of  North  America.  From  October  to  March  the 
States  lying  in  the  area  between  Connecticut  and  Iowa  and  south  to 


The  Crow  in  Its  Relation  to  Agriculture.  7 

Virginia  and  Oklahoma  harbor  crows  in  extremely  large  numbers, 
and  damage  often  results  in  places  where  crops  are  left  in  the  fields 
until  late  in  fall.  On  the  accompanying  map  (fig.  2)  are  recorded 
crow  roosts  known  to  have  been  occupied  in  the  winter  of  1911-12. 

ECONOMIC   STATUS. 

What  a  bird  eats  or  does  not  eat  is  the  first  question  to  be  answered 
in  an  inquiry  into  its  economic  status.  To  determine  with  accuracy 
the  various  items  entering  into  its  diet  nothing  has  been  found  more 
reliable  than  the  examination  of  stomach  contents.  In  the  case  of  the 
crow  such  examination  has  been  made  of  an  excellent  series  of  2,118 
stomachs,  collected  in  40  States,  the  District  of  Columbia,  and  several 
Canadian  Provinces.  Of  these  stomachs  1,340  were  of  adult  crows 
and  778  of  nestlings. 

ANIMAL  FOOD. 

About  28  per  cent  of  the  yearly  food  of  the  adult  crow  consists  of 
animal  matter.  In  this  are  found  insects,  spiders,  millipeds,  crus- 
taceans, snails,  the  remains  of  reptiles,  amphibians,  wild  birds  and 
their  eggs,  poultry  and  their  eggs,  small  mammals,  and  carrion. 

INSECTS. 

Over  two-thirds  of  the  animal  food,  or  about  a  fifth  of  the  whole 
diet  of  the  crow,  is  composed  of  insects,  and  these  include  many  of 
the  most  destructive  pests  with  which  the  farmer  has  to  deal.  The 
crow  is  primarily  a  terrestrial  feeder.  Its  share  of  insects,  there- 
fore, is  made  up  almost  exclusively  of  species  found  on  or  near  the 
ground,  or  those  which  it  secures  from  beneath  the  surface  by  turn- 
ing over  sticks,  clods  of  earth,  or  dung.  The  latter  is  a  common 
method  of  feeding  employed  diligently  by  the  crow  from  early 
spring  to  the  beginning  of  autumn,  when  the  usual  crop  of  grass- 
hoppers furnishes  a  more  accessible  supply  of  food. 

Beetles  of  various  kinds  constitute  about  7.5  per  cent  of  the  crow's 
annual  food.  They  are  a  promiscuous  lot,  some  beneficial,  some  neu- 
tral, and  others,  which  comprise  the  major  portion,  highly  injurious. 
Among  the  injurious  are  May  beetles  and  their  larvae,  white  grubs; 
also  click  beetles,  weevils,  and  some  of  the  ground  beetles  which  have 
vegetarian  food  habits.  Orthoptera,  including  grasshoppers,  locusts, 
and  crickets,  form  about  an  equal  quantity  (7.33  per  cent),  but 
the  damage  this  order  of  insects  inflicts  far  exceeds  that  done  by  the 
various  beetles  eaten.  The  short-horned  grasshoppers  especially  are 
destructive,  and,  while  these  insects  have  never  been  such  serious 
pests  in  the  Eastern  States  as  in  some  parts  of  the  West,  the  annual 
toll  taken  by  them  throughout  the  country  amounts  to  many  mil- 
lions of  dollars.  In  August  and  September  grasshoppers  form 


Farmers'  Bulletin  1102. 


The  Crow  in  Its  Relation  to  Agriculture. 


0 


nearly  one-fifth  of  the  crow's  food.  Caterpillars  form  about  1.5  per 
cent  of  the  diet  of  the  adults;  nestlings,  however,  eat  nearly  four 
times  as  much.  Other  insects,  as  bees,  wasps,  ants,  flies,  and  true 
bugs,  are  taken  in  only  small  quantities,  and  the  economic  problems 
involved  are  not  important. 

The  numbers  of  the  various  insects  eaten  during  different  months  of 
the  year  are  often  indicative  of  their  period  of  abundance.  Early  in 
spring,  for  instance,  few  May  beetles  or  other  scarabseid  beetles  are 
eaten;  but,  beginning  in  April,  they  form  about  5  per  cent  of  the 
crow's  food,  and  in  May  the  presence  of  the  annual  crop  of  May 
beetles  is  indicated  by  the  extraordinary  percentage  of  20.99.  Like- 
wise the  monthly  increase  of  grasshoppers  from  May  to  September 
is  shown  in  the  crow's  diet  by  the  approximate  percentages  of  4,  6, 14, 
19.  and  19,  representing  the  proportion  of  these  in  the  food  taken. 
The  height  of  the  caterpillar  season  also  is  indicated  by  the  ap- 
proximate percentages  of  1,  3,  6,  and  2,  for  the  months  of  April,  May, 
June,  and  July,  respectively. 

TABLE  I. — Monthly  percentages  of  the  principal  food  items  of  the  adult  crow. 


Kind  of  food. 

Jan. 

Feb. 

Mar. 

Apr. 

May. 

June. 

July. 

Aug. 

Sept. 

Oct. 

Nov. 

Dec. 

Av- 
erage. 

May  beetles,  etc  
Ground  beetles  
G  rasshopper  s 

0.18 
.07 
.51 

1.19 
.10 
1.14 

1.04 
.26 
56 

4.98 
2.30 
1  84 

20.79 
5.54 
4  29 

10.06 
3.24 
5  83 

4.47 
2.13 
14  04 

5.26 
1.76 
19  14 

0.91 
2.31 
19  24 

0.54 
.14 

8  68 

0.77 
.74 
10  73 

1.17 
.19 
2  07 

4.28 
1.56 
7  34 

Caterpillars  

.18 

.41 

1.36 

1.13 

2.71 

6  41 

1  95 

.62 

2  12 

1  19 

30 

39 

1  56 

Miscellaneous  insects. 
Carrion  

.35 
8.95 

2.01 
2.45 

1.36 
2.66 

4.47 
5.24 

6.44 
2.13 

10.41 
1.48 

11.26 
.29 

8.29 
.95 

3.06 
2.69 

.96 
.32 

1.62 
1  44 

.67 
2  37 

4.23 
2  58 

Other  miscellaneous 
animal  matter  
Corn  

4.70 
51.95 

3.67 
43.19 

8.81 
36.85 

14.13 
35.28 

10.56 
33.26 

9.55 
20  53 

10.14 
9  13 

3.38 
17  96 

1.99 

29  60 

2.46 
54  33 

3.14 
63  93 

6.32 
65  00 

6.57 

38  42 

Other  grain 

7.00 

9  74 

34  22 

20  90 

8  43 

10  20 

20  22 

22  80 

8  33 

7  08 

2  67 

89 

12  70 

Cultivated  fruit  
Wild  fruit  

2.55 
19.76 

3.42 
19.57 

.26 
10.65 

2.74 
5  06 

.91 

3  49 

14.12 

7  28 

9.31 
14  05 

5.79 
13  67 

1.66 
25  82 

2.40 
90  50 

.07 
12  94 

1.36 
14  75 

3.74 
13  96 

Weed  seeds  and  rub- 
bish 

3  80 

13  11 

1  97 

1  93 

1  45 

89 

3  01 

38 

2  27 

1  40 

1  65 

4  82 

3  06 

The  size  and  the  voracious  appetites  of  crows  make  these  birds 
especially  valuable  in  times  of  outbreak  of  one  or  another  of  the  insect 
pests  upon  which  they  feed.  In  the  stomach  of  a  crow  collected  in 
April  were  the  remains  of  85  May  beetles,  and  these  formed  less  than 
half  the  food;  in  another  were  72  wireworms;  and  in  a  third  were 
fragments  of  123  grasshoppers.  Twelve  birds  in  a  series  collected  in 
Manitoba  had  fed  on  grasshoppers  at  the  average  rate  of  57  each, 
and  one  crow  secured  in  Michigan  had  eaten  483  small  caterpillars. 
Nestling  crows,  whose  rapidly  growing  bodies  require  even  greater 
quantities  of  insect  food  than  the  adults,  often  excel  their  parents  in 
the  good  work  of  insect  destruction.  One  brood  of  4  had  consumed 
418  grasshoppers,  and  another  brood  of  7  had  made  away  with  585 
during  a  few  hours  before  they  were  collected.  Of  a  total  of  157 
nestling  crows  secured  in  Kansas  in  1913, 151  had  been  fed  on  grass- 
hoppers. Caterpillars,  always  a  favorite  source  of  food  for  nestling 
172161°— 20 2 


10  Farmers'  Bulletin  1102. 

birds,  were  present  in  over  a  third  of  the  778  nestling-crow  stomachs 
examined. 

Summing  up,  it  may  be  said  that  the  character  of  the  insect  food 
of  the  crow  leaves  little  to  be  desired  and  becomes  the  strongest  argu- 
ment in  the  bird's  favor.  While  fully  applicable  to  the  adult  birds, 
this  statement  is  doubly  true  of  the  nestlings,  whose  rapidly  growing 
bodies  require  enormous  quantities  of  such  readily  digestible  food 
as  is  furnished  by  soft-bodied  insects. 

SPIDERS,  FISHES,  REPTILES,  ETC. 

In  the  other  animal  food  of  the  crow  are  items  that  reflect  some 
of  the  bird's  less-admired  habits.  The  aggregate  consumption  of 
spiders,  millipeds,  crustaceans,  mollusks,  fishes,  and  carrion  may  be 
considered  as  having  a  slight  influence  for  good,  but  the  destruction 
of  beneficial  toads,  frogs,  and  small  snakes  is  against  the  bird.  For- 
tunately, however,  the  quantity  of  such  material  eaten  is  small, 
slightly  more  than  1  per  cent  of  the  yearly  food. 

WILD  BIRDS  AND  THEIR  EGGS. 

Because  of  its  depredations  on  small  wild  birds  and  its  destruction 
of  the  nests  and  eggs  of  larger  game  species,  the  crow  has  received 
the  condemnation  of  bird  lovers  and  sportsmen.  While  stomach 
examination  has,  to  an  extent,  verified  this  accusation,  it  has  at  the 
same  time  disproved  extravagant  statements.  About  a  third  of  1 
per  cent  of  the  annual  food  of  adult  crows  and  1.5  per  cent  of  that 
of  nestlings  is  derived  from  wild  birds  and  their  eggs,  and  about  1 
in  every  28  adult  crows  and  1  in  every  11  nestlings  examined  had 
eaten  such  food.  In  the  case  of  the  nestlings,  however,  this  ratio 
gives  an  exaggerated  idea  of  the  work  done,  as  in  many  instances 
several  members  of  a  brood  had  fed  on  parts  of  the  same  victim.  A 
mitigating  circumstance  in  connection  with  the  destruction  of  the 
eggs  of  wild  birds  lies  in  the  fact  that  most  of  it  is  done  during  the 
nesting  ssason  of  the  crow — a  time  early  enough  in  the  year  to 
allow  the  species  attacked  to  lay  a  second  set  of  eggs  that  will 'be 
little  molested  by  crows.  Nevertheless,  on  game  farms  and  preserves, 
and  in  suburban  districts  where  it  is  the  desire  to  foster  small  birds, 
the  crow  population  must  be  held  in  check. 

POULTRY  AND  THEIR  EGGS. 

The  crow's  depredations  on  poultry  and  their  eggs  are  governe 
largely  by  local  conditions.  The  proximity  of  a  crow's  nest 
taining  a  brood  of  voracious  young,  the  accessibility  of  some 
ticular  poultry  yard,  and  the  overdevelopment  in  certain  individual 
crows  of  this  obnoxious  habit,  are  factors  accountable  for  most  of 
the  losses  to  poultry  raisers  from  crows.  Reports  of  striking  simi- 


The  Crow  in  Its  Relation  to  Agriculture.  11 

larity  often  come  from  localities  widely  separated,  while  circum- 
stances diametrically  opposite  have  been  reported  from  neighboring 
farms.  Food  of  this  sort  forms  an  extremely  small  part  of  the  annual 
diet  of  the  crow,  less  than  1  per  cent  (0.57)  of  the  adult's  and  1.6 
per  cent  of  the  nestling's.  As  in  feeding  on  wild  birds,  the  crow's 
visits  to  the  poultry  yard  are  most  frequent  during  the  period  when 
it  has  young  to  feed ;  as  a  consequence,  successful  protective  measures 
undertaken  in  May,  June,  and  July  will  reduce  to  a  minimum  the 
crow's  depredations  on  poultry. 

MAMMALS. 

In  feeding  on  mammals  the  crow  supplements  the  good  work  of 
hawks  and  owls  by  tending  to  hold  in  check  rodent  pests.  Such 
food  forms  1.6  per  cent  of  the  diet  of  adult  crows  and  8.8  per  cent 
of  nestlings.  Their  favorite  mammal  food  consists  of  young  cotton- 
tail rabbits.  While  the  crow  does  molest  such  live  stock  as  young 
lambs  and  swine,  this  is  only  an  occasional  habit  when  the  bird  is 
hard  pressed  for  food.  Fortunately  such  work  is  not  common  and 
the  aggregate  loss  of  this  kind  is  negligible. 

CARRION  AND  THE  DISTRIBUTION  OF  LIVE-STOCK  DISEASES. 

As  a  carrion  feeder  the  crow  ably  supplements  the  good  work  of 
the  turkey  buzzard,  especially  along  river  banks  and  tidal  flats, 
where  dead  fish  furnish  a  supply  of  animal  matter  much  needed 
during  winter.  But,  from  its  carrion- feeding  habits,  the  crow  has 
been  accused  of  being  a  potent  agency  in  the  transmission  of  live- 
stock diseases,  especially  hog  cholera.  No  doubt  the  transmission  of 
this  disease  by  the  crow  is  within  the  range  of  possibilities,  either 
by  the  carrying  of  virus  attached  to  its  feet,  bill,  or  other  parts  of 
its  body  or  possibly  by  the  depositing  of  infected  excreta  after  the 
bird  had  fed  on  the  body  of  an  animal  that  had  died  from  the  dis- 
ease. However,  by  the  immediate  burying  of  the  dead  bodies  of  dis- 
eased animals  and  the  employment  of  rigid  sanitary  measures  in  out- 
breaks of  this  kind,  the  incentives  which  usually  attract  these  birds 
may  be  eliminated.  It  is  well  to  add  that  many  other  agents  in  the 
spread  of  such  diseases,  including  dogs,  cats,  and  innumerable  in- 
sects, are  as  potent  in  the  dissemination  of  bacteria  as  are  crows. 
All  of  these  can  be  made  innocuous  by  thorough  methods  of  sanita- 
tion, while  the  extermination  of  the  crow  would  eliminate  only  one 
of  many  means  by  which  such  diseases  are  transferred. 

VEGETABLE  FOOD. 

CORN. 

Vegetable  matter  forms  nearly  72  per  cent  of  the  adult  crow's 
yearly  food,  and  over  half  of  it  consists  of  corn.  In  November,  De- 


12  Farmers'  Bulletin  1102. 

cember,  and  January  this  grain  forms  over  half  the  diet,  but  most  of 
it  is  waste,  gleaned  from  scattered  unharvested  ears.  During  the 
sprouting  season  of  April  and  May,  corn  constitutes  about  a  third  of 
the  food,  and  at  the  harvest  in  October  it  again  supplies  over  half. 
Of  1,340  adult  crows  collected  in  varying  numbers  in  every  month 
of  the  year,  824  (over  61  per  cent)  had  fed  on  corn. 

It  is  the  belief  of  some  farmers  that  the  depredations  on  this 
grain  in  sprouting  time  are  due  largely  to  the  nestlings'  desire  for 
the  soft,  germinating  kernel.  Stomach  analysis  has  disproved  this, 
and  has  showed  that  corn  formed  less  than  an  eighth  of  the  young 
crow's  food,  one-third  the  quantity  taken  by  the  adults  during  ap- 
proximately the  same  time.  Injury  to  this  crop  may  be  either  to 
sprouting  corn,  to  corn  "  in  the  milk  "  or  in  the  "  roasting-ear  "  stage, 
or  when  the  ripened  grain  has  been  stacked  in  shocks.  Of  the  three, 
the  last  form  of  injury  is  the  least  serious;  the  pulling  of  sprouting 
corn  sometimes  results  in  heavy  losses,  but  fortunately  such  damage 
may  be  reduced  by  the  use  of  deterrents;  the  damage  to  corn  in 
the  roasting  ear  is  the  most  vexatious  form  of  damage  to  this  grain 
of  which  the  crow  is  guilty.  It  is  not  so  much  the  corn  the  crow 
actually  eats  at  this  time,  as  it  is  the  subsequent  injury  resulting 
from  water  entering  the  ears  from  which  the  husks  have  been 
partially  torn,  that  makes  such  attacks  among  the  most  serious  with 
which  the  farmer  has  to  contend. 

OTHER  GRAINS. 

Of  the  smaller  grains,  which  together  form  about  an  eighth  of  the 
food  of  the  adult  crow,  wheat  is  the  favorite.  This  was  present  in 
227  of  the  1,340  stomachs  examined,  and  it  apparently  takes  the 
place  of  corn  in  the  crow's  diet  in  regions  where  corn  is  not  raised 
extensively.  Stomachs  collected  in  the  Northwest  illustrate  this. 
When  attacks  upon  wheat  are  made  in  sowing  or  sprouting  time,  the 
depredations  of  a  single  crow,  limited  only  by  a  most  ample  gizzard, 
may  be  of  considerable  consequence.  Oats  are  eaten  much  less  fre- 
quently than  wheat,  and  when  it  is  considered  that  oats  are  readily 
available  at  all  times  of  the  year  in  horse  droppings,  the  quantity  of 
this  grain  in  the  diet  of  the  crow  need  not  much  concern  the  farmer. 
Injury  to  kafir  corn  (sorghum)  in  autumn  has  been  reported  from 
Kansas  and  Oklahoma,  usually  in  the  vicinity  of  roosts,  where  many 
thousands  of  crows  congregate  and  feed  over  a  comparatively  small 
area  day  after  day  during  fall  and  winter.  Buckwheat  also  is  oc- 
casionally eaten,  but  by  far  the  largest  portion  of  it  is  waste. 

OTHER  CROPS. 

A  number  of  other  crops  are  subject  to  damage  by  crows.  In 
Southern  States,  depredations  on  ripening  watermelons  have  some- 


The  Crow  in  Its  Relation  to  Agriculture.  13 

times  resulted  in  heavy  losses.  Apples,  peanuts,  pecans,  and  almonds 
are  less  frequently  injured ;  while  the  aggregate  losses  to  such  crops  as 
beans,  peas,  figs,  oranges,  grapes,  and  cherries  are  insignificant. 

WELD  FRUITS. 

Only  about  14  per  cent  of  the  adult  crow's  sustenance  is  at  present 
derived  from  wild  fruits  and  nuts,  a  source  whence  it  originally  ob- 
tained all  of  its  vegetable  food.  This  part  of  its  diet  is  secured  from 
a  variety  of  sources,  but  chiefly  from  acorns  and  chestnuts.  Fruit  of 
the  various  sumachs,  poison  ivy  and  poison  oak,  bayberry,  dogwood, 
sour  gum,  wild  cherries,  grapes,  Virginia  creeper,  and  pokeberry  are 
also  common  ingredients  in  the  food. 

DISTRIBUTION  OF  SEEDS. 

The  mere  consumption  of  wild  fruit  by  the  crow  involves  nothing 
of  economic  importance,  but  as  its  digestive  processes  destroy  prac- 
tically none  of  the  embryos  of  the  seeds,  the  bird  acts  as  an  important 
distributor  of  certain  noxious  plants,  as  poison  ivy  and  poison  oak. 
In  this  work,  however,  it  is  only  supplementing  the  activities  of  the 
many  other  native  birds  which  feed  on  these  seeds,  often  to  a  greater 
extent  than  does  the  crow.  Furthermore,  as  most  of  these  seeds  are 
eaten  by  the  crow  during  the  winter,  a  large  part  of  those  regurgi- 
tated are  deposited  at  their  roosts,  often  in  dense  stands  of  timber, 
where  the  chances  for  sprouting  are  poor. 

TABLE  II. — Percentages  of  the  principal  food  items  of  the  nestling  crow. 


17.44 


3.90 


2.59 


14.60 


2.61 


5.34 


1.88 


9.68 


1.78 


7. 04  1.  57 


6.22 


I 

o 

2.61 


3.95 


11.91 


4.58 


SUMMARY  OF  FOOD  HABITS. 

The  crow's  consumption  of  insects  presents  the  strongest  argu- 
ment in  the  bird's  favor.  About  a  fifth  of  its  diet  is  secured  from 
the  insect  world,  and  among  the  pests  it  destroys  are  some  of  the 
most  troublesome  with  which  the  farmer  has  to  contend.  Many  of 
the  insects  it  eats  are  taken  early  in  spring,  when  their  life  cycles 
are  at  the  lowest  ebb  and  when  their  destruction  results  in  the  greatest 
good. 

Conspicuous  among  such  food  items  are  May  beetles  and  their  de- 
structive larvae,  white  grubs,  of  which  the  crow  is  an  effective  enemy. 
In  its  consumption  of  grasshoppers  the  crow  probably  renders  man 
its  greatest  individual  service,  and  in  regions  where  these  insects  are 


14 


Farmers'  Bulletin  1102. 


abundant  their  nymphs  form  the  principal  insect  food  of  the  nest- 
lings. Other  creatures  in  the  destruction  of  which  the  young  exceed 
the  adults  include  caterpillars  and  spiders.  The  latter,  however,  are 
predacious  and  to  a  great  extent  beneficial. 

The  crow's  feeding  on  reptiles  and  amphibians  is  on  the  whole  not 
to  the  best  interests  of  man.  but  fortunately  the  highly  beneficial 
toads  are  found  in  the  food  less  frequently  than  the  more  aquatic 
frogs  and  salamanders.  In  feeding  on  the  eggs  and  young  of  small 


If 

II 


FIG.  4.— Food  of  nestling  crows.    The  proportions  of  the  various  elements  are  represented  by  the  rela- 
tive sizes  of  the  sectors.    In  Table  II  the  same  information  is  presented  in  percentages. 

insectivorous  and  game  birds  the  crow  commits  a  serious  offense,  and 
in  the  vicinity  of  game  farms  and  preserves  the  bird  must  be  held  in 
check  if  other  species  are  to  exist  in  concentrated  numbers.  This 
offense  is  mitigated  somewhat  by  the  fact  that  most  of  the  depreda- 
tions on  eggs  occur  early  enough  in  the  season  to  permit  the  raising 
of  a  second  brood  at  a  time  when  there  is  little  or  no  danger  from 
the  crow.  The  molesting  of  poultry  is  an  injurious  habit  against 
which  protective  measures  are  effective  under  any  but  the  shift-by- 


The  Crow  in  Its  Relation  to  Agriculture.  15 

itself  method  of  caring  for  fowls.  A  little  attention  to  the  screening 
of  young  chicks  and  the  suitable  housing  of  setting  hens  will  obviate 
most  losses  of  this  kind.  In  its  feeding  on  small  mammals,  its 
annoyance  of  young  live  stock,  and  its  consumption  of  carrion,  the 
crow  has  tendencies  about  equally  divided  between  good  and  bad. 
The  accusation  that  it  is  a  dominant  factor  in  the  distribution  of 
live-stock  diseases  has  little  substantiating  evidence. 

Of  the  vegetable  food,  corn  is  the  principal  item.  It  is  the  crow's 
staff  of  life  and  furnishes  over  38  per  cent  of  its  annual  sustenance. 
In  the  consumption  of  this  grain  the  bird  comes  in  most  frequent  con- 
flict with  the  farmer.  Much  of  the  corn  eaten,  however,  is  secured 
from  October  to  March,  when  waste  grain  necessarily  forms  a  large 
part  of  the  supply.  Deterrents,  as  coal  tar,  on  the  seed  have  lessened 
losses  to  sprouting  grain,  especially  in  small  isolated  fields,  but,  when 
"  in  the  roasting  ear,"  the  corn  crop  is  subject  to  annoying  and  de- 
structive attacks  by  the  crow,  difficult  to  prevent.  The  crow  also 
levies  a  certain  toll  on  small  grains,  as  wheat  and  sorghums ;  melons 
are  subject  to  attack  and  even  cultivated  fruits  at  times  are  damaged. 

The  offenses  of  which  the  crow  has  been  accused  outnumber  its 
good  deeds,  but  this  does  not  mean  that  they  are  equal  in  importance. 
Many  of  the  crow's  depredations  may  be  lessened  or  entirely  pre- 
vented by  protective  measures,  while  in  its  preying  on  insects  it  does 
work  that  can  ill  be  spared.  An  overabundance  of  these  birds  is  not 
to  the  best  interests  of  the  farmer,  but,  on  the  other  hand,  extermina- 
tion of  the  crow  would  result  in  taking  away  a  most  effective  enemy 
of  certain  insect  pests.  Consequently  the  instituting  of  control  meas- 
ures is  justifiable  locally  where  the  birds  are  taking  more  than  a  fair 
share  of  the  crops  in  return  for  good  services  rendered,  while  in  other 
sections  where  crows  occur  in  normal  numbers  they  may  better  be 
allowed  to  exist  unmolested. 

PROTECTION   OF   CROPS   AND   POULTRY. 

FRIGHTENING  DEVICES. 

It  is  not  necessary  to  describe  in  detail  the  many  well-known  de- 
vices employed  as  "scarecrows."  The  time-honored  straw-stuffed 
human  effigy  is  the  one  most  frequently  used,  though  often  it  fails  to 
accomplish  its  purpose.  Various  unusual  objects,  as  pieces  of  shining 
tin  moving  in  the  wind  or  glass  bottles  hung  about  fields,  windmills 
operating  a  noise-producing  mechanism,  newspapers  placed  on  the 
ground,  twine  stretched  about  and  across  fields  from  poles  stationed 
at  intervals  around  them,  as  well  as  bodies  of  dead  crows  hung  in 
conspicuous  places,  have  been  successful  in  some  instances.  Poultry 
yards  especially  have  been  protected  from  the  ravages  of  crows  by 
strands  of  cord  stretched  across  at  intervals  and  at  a  height  of  6  or  8 


16  Farmers'  Bulletin  1102. 

feet  from  the  ground.  One  or  another  of  these  methods  has  met  with 
varying  success  on  occasion,  but  sometimes  none  will  produce  the  de- 
sired results.  None  can  be  considered  infallible. 

DETERRENTS. 

Coal  tar. — Experience  has  shown  that  damage  to  corn  and  other 
grains  at  sprouting  time  may  be  lessened  by  special  treatment  of 
the  seed.  While  the  application  of  deterrents  to  the  seed  grain  has 
disadvantages,  in  that  it  involves  additional  labor  at  planting  time, 
tends  to  retard  germination  in  periods  of  dry  weather,  and  can  not 
be  considered  an  absolute  cure,  the  measure  of  success  of  many  farm- 
ers who  have  in  this  manner  secured  relief  from  crow  depredations 
warrants  a  description  of  the  methods  used. 

One  of  the  most  successful  deterrents  is  coal  tar,  a  cheap  by-product 
in  the  manufacture  of  illuminating  gas,  which  may  be  secured  at 
gas  works  or  at  some  paint  shops.  It  is  a  dark,  heavy  liquid  of 
about  the  consistency  of  thin  molasses  and  emits  a  strong,  gassy 
smell  for  some  time,  even  after  the  grain  treated  with  it  has  become 
thoroughly  dry.  When  used  in  the  quantities  here  recommended, 
coal  tar  in  no  way  injures  the  germinating  qualities  of  the  seed. 
This  important  qualification  is  not  possessed  by  certain  other  sub- 
stances, sometimes  recommended  as  crow  deterrents.  Experiments 
conducted  by  the  writer  also  have  shown  that  in  periods  of  normal 
rainfall  germination  is  but  slightly  retarded  by  the  coal-tar  treat- 
ment, though  in  periods  of  drought  the  retardation  may  be  several 
days. 

Coal  tar  should  be  used  in  the  proportion  of  about  a  tablespoonful 
to  half  a  bushel  of  seed  grain,  the  grain  having  been  previously 
heated  by  the  application  of  warm  water,  and  then  drained.  A  con- 
tinued stirring  of  the  grain  will  eventually  result  in  an  even  coating 
of  tar.  The  seed  may  then  be  spread  out  on  a  dry  surface  or  may 
be  dried  by  the  application  of  an  absorbent  medium,  as  ashes,  land 
plaster,  or  powdered  earth.  When  thoroughly  dry  it  may  be  used  in 
a  planter. 

Deterrents  are  commonly  used  by  farmers  of  the  North  Atlantic 
States  and  to  a  lesser  extent  by  farmers  of  the  South  Atlantic  States. 
In  the  extensive  corn-raising  regions  of  Illinois,  Missouri,  and  Iowa, 
corn  is  seldom  tarred,  probably  because  it  is  planted  on  so  large  a 
scale  that  losses  to  the  individual  farmer  are  less  severe. 

Bed  lead. — Another  substance  used  as  a  deterrent  is  red  lead.  This 
appears  to  have  been  used  first  in  Europe,  where  it  met  with  con- 
siderable success.  The  grain  is  first  given  a  thin  glue  size,  and  is 
then  drained  and  dusted  with  red  lead  until  well  colored.  Though 
this  process  has  been  used  but  little  in  this  country,  its  success  in 
deterring  birds  in  Europe  warrants  a  further  trial  here. 


The  Crow  in  Its  Relation  to  Agriculture.  17 

Other  deterrents. — A  few  years  ago  the  Kansas  State  Agricultural 
College  Experiment  Station  conducted  a  series  of  experiments  on 
seed  grain  to  ascertain  the  usefulness  of  certain  deterrents  against 
burrowing  animals.  Incidentally  the  effect  of  these  various  sub- 
stances upon  the  germinating  powers  of  the  seed  was  investigated. 
In  his  report  on  this  work,  Theo.  H.  Scheffer *  says  in  part  that  kero- 
sene, crude  petroleum,  copperas,  crude  carbolic  acid,  fish  oil,  and 
spirits  of  camphor,  when  used  in  sufficient  quantity  or  strength  to 
impart  an  odor  to  the  corn,  seriously  injure  the  germinating  powers 
of  the  grain ;  and  that  to  treat  the  seed  with  any  of  these  substances 
in  such  small  quantity  or  dilute  form  as  not  to  injure  the  germ  is  a 
waste  of  time,  for  the  slight  taste  or  odor  imparted  is  soon  dissipated 
in  contact  with  the  soil. 

Similar  experiments2  conducted  by  B.  M.  Duggar  and  M.  M. 
McCool,  at  the  Agricultural  Experiment  Station  of  Cornell  Univer- 
sity, indicated  that  of  a  number  of  substances  employed,  turpentine 
emulsion  and  an  anilin  oil  solution  seriously  affected  germination. 
Such  substances  should  be  carefully  avoided. 

The  manufacture  of  deterrents  for  use  on  seed  grain  has  been 
undertaken  on  a  moderate  scale  in  this  country,  and  a  few  articles 
of  this  nature  also  have  been  imported.  Most  of  these  appear  to  use 
coal  tar  or  closely  related  products  as  a  base;  one  at  least  contains 
a  copper  salt  and  is  a  poison ;  while  the  merit  of  one  imported  deter- 
rent appears  to  be  based  on  the  fact  that  the  treated  seed  is  a  brilliant 
blue.  None  of  those  tested  by  the  writer  has  had  any  harmful  effect 
on  the  seed ;  but  there  is  no  evidence  that  any  of  these  manufactured 
substances  is  superior  to  coal  tar  as  a  deterrent  when  the  latter  im- 
properly applied. 

SCATTERING  GRAIN. 

Many  farmers  have  had  considerable  success  in  protecting  their 
sprouting  crop  by  spreading  broadcast  over  the  fields  a  quantity  of 
grain  previously  softened  with  water.  This  the  birds  take,  leaving 
untouched  that  which  has  been  planted.  It  has  been  found  that  a 
comparatively  small  quantity  sacrificed  in  this  way  during  the  short 
period  of  a  week  or  10  days  when  spouting  corn  is  subject  to  damage 
has  often  prevented  loss  to  the  growing  crop. 

POISONING. 

Though  the  crow  would  be  a  most  difficult  bird  to  eradicate  over 
any  considerable  area  by  a  campaign  of  poisoning — a  fact  due  largely 
to  the  bird's  wariness — such  a  method  has  been  found  an  effective 
means  of  protecting  crops.  When  once  a  flock  of  these  birds  have 

1  Kansas  State  Agr.  Coll.  Exp.  Sta.,  Circ.  1,  p.  3,  Apr.  28,  1909. 

2  Cornell  Univ.  Agr.  Exp.  Sta.,  Circ.  6,  pp.  14-16,  May,  1909. 


18  Farmers'  Bulletin  1102. 

learned  through  the  loss  of  one  or  several  of  their  number  that  a 
certain  area  has  been  baited  with  poisoned  food  they  are  inclined 
to  avoid  it  for  some  time  at  least.  In  conducting  such  operations, 
however,  local  regulations  governing  the  distribution  of  poison  must 
be  scrupulously  observed,  and  as  there  is  always  an  element  of  danger 
connected  with  the  distribution  of  poison  about  thickly  settled  re- 
gions, its  use  should  be  limited  and  judicious. 

Corn  is  the  bait  usually  employed  in  poisoning  crows,  and  it  is 
generally  prepared  by  simply  steeping  the  grain  in  a  strong  strych- 
nine solution.  If  made,  however,  according  to  the  following  direc- 
tions it  will  kill  more  quickly  and  its  effectiveness  will  last  for  a 
considerable  time  when  exposed  to  weather: 

Corn 20  quarts 

Strychnine  (powdered) 1  ounce 

Starch 2  tablespoonfuls 

Water 1$  pints 

Put  the  starch  and  strychnine  in  the  water  and  heat  to  boiling,  stirring 
thoroughly  after  the  starch  begins  to  thicken.  Pour  this  mixture  over  the  corn 
and  stir  till  every  kernel  is  coated.  The  seed  may  then  be  spread  out  and  dried. 

Experiments  conducted  in  Klickitat  County,  Washington,  demon- 
strated that  where  crows  are  troublesome  to  green  almonds,  relief 
may  be  secured  by  using  these  nuts  as  bait,  prepared  by  splitting  and 
inserting  a  quantity  of  a  strychnine-saccharine  mixture  of  about  the 
size  of  a  kernel  of  wheat.  The  poison  mixture  is  composed  of  8  parts 
of  strychnine  alkaloid  and  1  of  saccharine.  The  poisoned  nuts  are 
then  placed  in  bare  spots,  two  or  three  under  each  tree.  While  such 
a  limited  number  of  baits  appears  to  be  wholly  insufficient  to  meet  a 
situation  where  a  flock  of  several  thousand  birds  settle  down  on  an 
orchard  of  a  few  acres,  the  results  secured  thus  far  have  been  most 
satisfactory.  In  attacking  an  almond  crop,  crows  will  first  alight  in 
the  tree  tops,  knock  down  a  few  nuts,  and  then  go  to  the  ground  to 
feed  on  them.  For  this  reason  conspicuously  placed  poisoned  baits 
of  this  kind  are  almost  certain  to  be  taken,  and  as  a  few  crows  killed 
or  seriously  affected  by  the  poison  will  suffice  to  make  others  shun 
the  area,  protection  has  been  secured  by  one  treatment  that  lasted  a 
week  or  10  days.  By  this  means  almond  crops  that  in  previous 
years  had  suffered  losses  sometimes  totaling  100  per  cent  were  but 
slightly  damaged. 

A  successful  bait  has  also  been  prepared  by  the  use  of  partially 
blown  hens'  eggs  into  which  a  small  quantity  of  strychnine  has  been 
injected.  This  has  been  effective  in  stopping  the  raids  of  the  poultry 
and  egg  stealing  crow.  It  should  always  be  placed  on  the  tops  of 
straw  stacks,  in  artificial  nests  erected  on  poles,  or  in  inclosures  from 
which  poultry  and  all  farm  animals  are  barred.  Strychnine  may 
even  be  conveyed  by  meat  or  carrion  used  as  baits,  but-the  difficulty 


The  Crow  in  Its  Relation  to  Agriculture.  19 

in  keeping  such  baits  away  from  domestic  animals  is  great ;  they  may 
be  used  to  best  advantage  in  winter,  when  crows  are  hard  pressed  for 
food. 

TRAPPING. 

Trapping  at  times  has  brought  relief  where  other  methods  have 
failed.  No  wholesale  reductions  in  the  number  of  crows  has  ever 
been  accomplished  by  this  method,  but  when  a  few  birds  have  been 
trapped  and  their  dead  bodies  have  been  left  exposed  in  the  fields, 
their  relatives  are  inclined  to  shun  the  immediate  vicinity.  Crows 
have  been  secured  mainly  in  steel  traps  carefully  baited  with  hens' 
eggs. 

SHOOTING. 

The  unusual  wariness  of  the  crow  has  limited  the  effectiveness  of 
firearms  in  reducing  its  numbers.  However,  these  birds  are  inclined 
to  shun  those  areas  where  the  shotgun  is  frequently  used.  The  use 
of  crow  decoys  and  crow  calls  has  been  resorted  to  with  such  success 
in  attracting  the  birds  within  gunshot  that  these  articles  are  now 
placed  on  sale  by  extensive  dealers  in  sporting  goods.  A  mounted 
specimen  of  an  owl  placed  in  a  conspicuous  position  and  within  easy 
gunshot  of  the  concealed  hunter  has  also  been  used  successfully  in 
attracting  numbers  of  crows  to  a  point  where  they  can  be  shot. 

In  eradicating  objectionable  winter  roosts  of  crows,  attacks  on 
several  successive  nights  by  a  number  of  men  with  firearms  will 
frequently  cause  the  birds  to  move  on.  Cartridges  loaded  with 
black  powder  are  better  than  those  containing  smokeless,  as  the  re- 
port is  more  deafening.  When  once  a  roost  has  been  removed, 
vigilance  must  be  employed  for  some  time  thereafter  to  keep  it  from 
being  reestablished.  In  places  where  the  discharge  of  firearms  was 
inadvisable,  Roman  candles  shot  among  the  roosting  birds  have 
brought  about  the  desired  results,  and  on  one  occasion  bunches  of 
firecrackers  thrown  up  into  the  tree  tops  caused  the  crows  to  seek  a 
more  peaceful  community. 

DESTROYING  NESTS. 

In  sections  where  woodlands  are  close  to  farmyards  containing 
exposed  nests  and  young  chicks,  the  destruction  of  a  few  crows' 
nests  will  greatly  lessen  depredations  on  poultry.  The  success  of 
this  measure  lies  in  the  fact  that  most  of  the  crow's  raids  on  the 
poultry  yard  are  prompted  by  its  desire  to  secure  food  for  its  young. 

SUMMARY. 

The  crow  is  a  bird  whose  size,  ability  to  survive  under  diverse  en- 
vironments, and  almost  omnivorous  food  habits  make  it  capable  of 
doing  both  serious  harm  and  extensive  good.  The  influence  of  the  race 
as  a  whole  for  good  and  harm  appears  to  be  about  equal.  Local 


20 


Farmers'  Bulletin  1102. 


conditions,  however,  greatly  affect  its  economic  status,  and  for  this 
reason  hasty  judgment  as  to  its  worth  should  not  be  rendered,  lest 
the  bird  be  persecuted  in  sections  wliere  it  is  actually  aiding  the 
farmer.  This  bulletin  has  aimed  to  point  out  briefly  the  benefits  to 
man  from  the  crow's  food  habits,  as  well  as  the  ways  in  which  the 
bird  may  do  harm.  Indiscriminate  killing  is  not  warranted,  and 
even  in  areas  where  the  crow,  is  doing  harm  preventive  measures 
will  often  put  a  stop  to  the  nuisance  and  allow  the  bird  to  continue 
what  good  work  it  may  be  doing  on  insects.  Among  the  preventive 
measures  are — 

(1)  The  use  of  coal  tar  or  other  deterrents  on  seed  grain. 

(2)  Scattering  grain  over  fields  where  the  crop  is  just  sprouting. 

(3)  Stretching  twine  about  and  across  fields  from  poles  stationed 
at, intervals.    A  network  of  such  strands  is  often  effective  in  pro- 
tecting poultry  yards. 

(4)  The  use  of  frightening  devices  and  the  hanging  up  of  the 
dead  bodies  of  crows  in  conspicuous  places. 

In  places  where  more  drastic  measures  are  necessary  the  killing 
even  a  few  crows  will  intimidate  others  and  these  will  usually  shi 
the  area  for  some  time.    Such  procedures  include— 

(1)  The  use  of  poison  (strychnine)  in  places  where  this  is  per- 
mitted by  law.     Corn  and  hens'  eggs  are  the  most  effective  baits. 

(2)  Trapping  by  means  of  steel  traps,  carefully  concealed  anc. 
baited  with  hens'  eggs. 

(3)  Destroying  nests — a  measure  that  will  most  irequently  put  a 
stop  to  the  poultry-raiding  activities  of  a  pair  of  crows  which  have 
their  nest  near  by. 

(4)  Shooting — the  hunter  being  aided  by  the  use  of  a  crow  call 
and,  where  possible,  also  by  a  mounted  owl  placed  conspicuously 

a  pole.     Several  night  attacks  by  a  number  of  men  equipped  wii 
shotguns  will  frequently  remove  objectionable  winter  roosts. 

o 


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